Apparatus for controlling well tools in well bores



D. E. YOUNG July 2, 196s APPARATUS FCR CONTROLLING WELL rrooLs 1N WELLBoREs Filed Oct. 24, 1965 2 Sheets-Sheet CoA/7R01. Eff/ANH LI I I I I IAPPARATUS FCR CONTROLLING WELL TOOLS IN WELL BORES Filed oct. 24. 1965 ID. E. YOUNG July 2, 1968 2 Sheets-Sheet 2.

Wm M gw 355% M M /f wm 11 f. l L\\\-\\.\\ |Wlller llllll Zay@ A froh/vsY United States Patent O 3,391,263 APPARATUS FOR CONTROLLING WELL TOOLSIN WELL BORES David E. Young, Houston, Tex., assiguor, by mesne assiguments, to Schlumberger Technology Corporation, Houston, Tex., acorporation of Texas Filed Oct. 24, 1965, Ser. No. 504,885 8 Claims.(Cl. 200-82) ABSTRACT F THE DISCLOSURE Apparatus for use in a lluid-lledwell bore to control electrical circuit means in a well tool includingcircuit control means, actuating means initially spaced from the controlmeans and movable over distances which are proportionately related topressure differentials imposed upon the actuating means in order toactuate the control means, and means for setting the initial spacingbetween the control means and the actuating means whereby the pressuredifferential required to actuate the control means can be preselected.

This invention relates generally to oil well equipment and, moreparticularly, to a method and apparatus for actuating downhole welltools in a fluid-filled Well bore.

In the drilling and completion of oil wells it is often desired toremotely -actuate downhole tools by opening or closing an electricalcircuit. Some examples of such tools are explosively actuated bridgeplugs and packers, shaped charge casing perforators, or setting toolsfor various packers and plugs. One method of actuating such tools is torun the tool into the well bore on a special conductor cable so that thepower source and switching mechanisms may be located at the earthssurface. Other methods of tool actuation employ time control clockswhich are subject to the disadvantage that they are 4beyond the controlof the operator once the Itool is lowered into the well.

The present invention concerns downhole actuation systems which can becontrolled by the operator at the earths surface and do not require aconductor cable.

Accordingly, an object lof the present invention is to provide a methodand apparatus for remotely actuating downhole well tools havingelectrical circuitry without the use of a conductor cable extending fromthe tool to the earths surface.

A further object of the invention is to provide a method and apparatusfor remotely actuating well tools in such a manner that actuation of thetool remains under the control of the operator at all times.

These and other objects of the present invention may be efectuated byproviding a pressure sensing means for actuating a well tool, whichmeans is pre-set to require pressure in excess of the calculated orotherwise determined hydrostatic pressure at tool actuation depth. Whenthefwell tool with the associated pre-set pressure sensing means islowered into the well bore to actuation depth, an additionalcontrollable pressure is applied to the fluid in the well boresufficiently in excess of the hydrostatic pressure to actuate thepressure-sensing means and thus, the well tool.

One embodiment of a suitable apparatus for practicing the inventioncomprises the combination with well bore apparatus having electricalcircuitry and which is adapted for insertion in a well bore containingfluid, of a housing having two chambers, one of which is open tohydrostatic well iluid pressure, and another chamber sealed fromhydrostatic pressures. A spring-biased piston extends into both chambersand is movable in response to pressure diterentials between thechambers. An actuator is attached to the piston for closing a switchupon a prede- 3,391,263 Patented July 2, 1968 ice termined travel of thepiston, and means are p'rovided for `adjus'tably positioning the switch.

The novel features of the present invention are set forth withparticularity in the appended claims. The present invention, both as toits structural organization and utility together with further objectsand advantages thereof, may best be understood by way of illustrationand example of one embodiment when taken in conjunction with theaccompanying drawings in which:

FIG. 1 is an elevational view, partially :broken away, showing thegeneral organization of the invention in connection with a well;

FIGS. 2JA and 2B are longitudinal sectional views showing the details ofconstruction of the control mechanism embodied in the present invention,FIG. 2B forming a lower continuation of FIG. 2A; and

FIG. 3 is a schematic view of an electrical system embodied in thepresent invention.

With reference to FIG. 1, numeral 11 indicates downhole well apparatusof the type which is actuated by manipulation of an electrical circuit.Examples of such apparatus are numerous and exemplified in Patents Nos.3,155,164 (bridge plug), 3,057,295 (casing cutter), 2,873,675 y(shapedcharge perforator) and 2,760,586 (setting tool and packer). To the upperend of the tool 11 is threadedly connected a battery case 12 containinga suitable power source such as a dry cell battery or the like.`Generally indicated as numeral 13 is a control mechanism threadedlyconnected at its lower end to battery case 12 and at its upper end toconnector sub .14, the entire apparatus being suspended in a well boreon a wire line 15. Well bore 16 contains the usual casing 17 which isfilled with a column of well control fluid. Wire line .15 extendsupwardly through the customary wellhead -18 and lubricator 1'9, thewellhead having a side outletZtl for connection with a suitable pump 21whereby :a controllable pressure may be 'selectively exerted on thecolumn of yiluid in the well bore.

The control mechanism 13, shown in detail in FIGS. 2A and 2B, iscomprised of an upper housing member 22 having an internal chamber 23which is open to hydrostatic well -fluid pressures through port 2`4, anda lower tubular housing member 25 having an internal chamber which issealed from hydrostatic well fluid pressures so as to be normallymaintained at atmospheric pressure. Housing member 22 has an upperthreaded part 26 for connection with sub 14. Near the upper end ofchamber 23 is a support plate 27 which is held in abutting relationshipwith an upwardly facing shoulder 28 by a suitable threaded ring memberZ9'. Support plate 27 has ports 30 formed therein. If desired, ailexible diaphragm member (not shown) may be placed above the supportplate 27 and upper chamber 23 filled with a hydraulic tluid forprotection of the internal parts in the chamber from damage by welllfluids. A spring connector member 31 having a bifurcated lower portionis threaded into support plate 217 centrally thereof and is securelyanchored -by a lock nut 32. A pin member 33 extends transversely betweenlegs 34 4of the bifurcated lower portion of the connector member 31 andthe upper end of a spring 35 is hooked over pin 3'3.

The lower end of upper chamber 23 is closed by a packing sub 36 which isscrew-threadedly engaged with the lower portion 37 of upper tubularhousing member 22- An O-ring 38 is positioned in a suitable groove inthe periphery of packing sub 36 and seals against the inner wall ofhousing member 22. Formed centrally in sub 36 is a bore 39 whichslidably receives a pressure differential responsive means in the formof an elongated piston member 40, one end of the piston member extendinginto upper chamber 23. An O-ring 41 is positioned in a groove in sub 36and seals against the exterior of piston member 40.

Another spring connector member 42 is threadedly secured to the upperend of piston member 40. The lower end of the above-mentioned spring 35is suitably attached to connector member 42 by a pin 43 extendingbetween the upwardly extending legs of the connector member.

The lower tubular housing member 25 is threadedly connected as at 44 tothe lower portion of upper tubular housing member 22 and extenddownwardly therefrom to form a lower chamber 45. A seal ring 46 sealsthe threaded joint between the upper and lower tubular housing members.The lower end portion of piston member 40 extends downwardly into -lowerchamber 45. Threadedly coupled to the lower end of the piston member isa connector 47 for a depending switch actuator in the form of a plungermember 48 made of a suitable electrically nonconductive material.

An upper portion of lower housing member 25 is counterbored at 49 toform an upwardly facing shoulder S0. An upper annular electricalinsulation ring 51 made of a suitable nonconductive synthetic resin isreceived between shoulder 50 and the lower end face 52 of housing member22. A lower portion of housing member 25 is counterbored at 53 to form adownwardly facing shoulder 54. A lower annular electrical insulationring 55 is held in place against Shoulder 54 by a retainer member 56.Received between the two insulation rings are circumferentiallyoppositely spaced conductor rails 57 made of copper or otherelectrically conductive material, the ends 58 of conductor rails 57being received in slots 59 formed in the lower and upper faces of theinsulation rings 51 and 55.

Slidably and adjustably mounted on each conductor rail is a contactcarriage 60 which is adapted for selective vertical positioning along aconductor rail and to be held in Such selected position by a set screw61. Each contact carriage carries an elongated resilient electricalcontact member 62 which extends radially inwardly in overlappingrelationship with the other of the contact members. It will beappreciated that the conductor rails 57 perform the functions ofadjustably supporting and positioning the contact carriages as well asserving as an integral part of a series electrical circuit. Suitableindicia 63 are provided on the conductor rails to aid in selectivelyspacing the contacts a predetermined distance below the switch actuator48.

Near the lower ends of conductor rails 57 are terminals 64 adapted forconnection with insulated electrical conductor wires. One wire 66extends to a terminal on battery 67. Another wire 68, in combinationwith wire 69 connected to the other of the battery terminals, provideleads to well tool 11. As will be readily apparent, sufficient downwardtravel of the piston member 40 will cause plunger member 48 to engageand close resilient contact members 62, thus completing a serieselectrical circuit comprised of power source 67, wires 66, 68, 69,conductor rails 57, contact carriages 60 and contacts 62 for actuationof well tool 11. It will be noted that the threaded joints betweenbattery case 12, lower tubular housing member 25, and well tool 11 aresealed by O-rings 70 so that lower chamber 45 is sealed from hydrostaticwell fluid pressures.

In the practice of the method and operation of the apparatus, theactuation depth (commonly determined by various logging operations) andthe weight of the fluid in the well bore are known and the hydrostaticwell fluid pressure at such depth can be readily calculated. Since lowerchamber 44 of the control mechanism is maintained at atmosphericpressure by being sealed from well fluid pressure, and since upperchamber 23 is open to well fluid pressure at port 24, the pressuredifferential across piston member 40 at tool actuation depth is easilydetermined. The effective area of piston member 40 and the springconstant for tension spring 35 are known. With these factors thedistance that the piston and plunger 47 will move downwardly into thelower chamber 45 when the tool is lowered to actuation depth is readilycalculated.

So that actuation of the well tool 11 will remain under the control ofthe operator at all times, and for the further purpose of preventingpremature closing of the electrical contacts due to such variables asshock pressure loads, temperature variations and mechanical inaccuraciesin the device, the contact carriage members 60 with attached contacts 62are selectively positioned during assembly and set along conductor rails57 the above-mentioned distance plus an additional distance away fromactuator 48. Thus, merely lowering the tool in the well bore toactuation depth will not cause the plunger to move downwardly enough toclose contacts 62. An additional controllable pressure must be exertedon the fluid column in the well casing to provide a suicient pressuredifferential across piston member 40 so that the actuator will move downthe total preset distance and close the contacts. With the controlmechanism thus, preset to sense hydrostatic Well fluid pressure plus anadditional controllable pressure, the tool is lowered into the well toactuation depth, When the operator desires to actuate the well tool 11,the additional controllable pressure is applied to the column of fluidin the casing 17 by means of the previously mentioned pump 21. Theactuator 48 will then move down the additional distance and closecontact-s 62, thus closing the electrical circuit and actuating thetool.

It will be appreciated, of course, that the additional pressure may beselectively applied and released by the operator which will result instroking the piston to close and open the switch repeatedly. Therefore,the electrical circuitry in well tool 11 may include a plurality ofelectrical circuits which can be sequentially operated by a meansresponsive to the selective application and release of the additionalcontrollable pressure. Such an arrangement is shown schematically inFIG. 3. One of the previously-mentioned contacts 62 of the controlmechanism 13 shown in FIG. 2 is electrically connected to the powersource 67. The other of the contacts 62 is electrically connected to thecoil 71 of a stepping switch 72, the coil being electro-mechanicallycoupled to a common switch arm 73 in a known manner. Common terminal 74of stepping switch 72 is also supplied with power from source 67 and ismovable from a position of coaction with a dead terminal 1 duringrunning in to positions of coaction with output terminals 2-4 andeventually to reset terminal 5. Thus, each time the contacts 62 areclosed by actuator 48 (FIG. 2) an electrical pulse from source `67through control mechanism 13 is effective to advance the common switcharm 73 sequentially Ifrom one terminal to the next for operating each ofa plurality of circuits A, B, C in well tool 11. By way of example,elements A, B, C in FIG. 3 may be circuits including squibs to be redfor sequential actuation of a plurality of shaped charge devices in acasing perforator.

As further shown in FIG. 3, a time delay means D may be electricallyconnected between the control mechanism 13 and the stepping switch 72,the delay circuit requiring a constant amplitude input signal for agiven time duration (one second for example) lbefore an output signal isgenerated to actuate the stepping switch 72. The delay circuit providesa safety factor against premature actuation of circuits A, B, C due toshock pressure loads Iwhich may act to close contacts 62 in controlmechanism 13. These circuits can not be fired unless the additionalcontrollable pressure is selectively maintained by the operator to keepthe contacts 62 closed for the time duration inherent in the operationof delay means D. p

Certain modications of an obvious nature may be made in the apparatusillustrated. For example, contacts 62 may be replaced by a microswitchwith conductor wires leading directly therefrom to other elements in thecircuit, in which case only one support rail would be needed. Of course,the support rail would not, in this case, form a part of the electricalcircuit as in the illus- U trated emdodiment. It will also beappreciated that the control mechanism is adapted to be run into thewell conduit on a tubing string.

It will be observed from the foregoing that applicant has provided amethod and apparatus for actuating downhole well tools wherein theelectrical circuitry of the tool may be manipulated lwithout the use ofa conductor cable extending from the tool to the earths surface andwherein the actuation of the tool will remain under the control of theoperator at all times. Since certain changes may be made in theabove-disclosed methods and apparatus without departing from the scopeof the inventive concept involved, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interepreted as illustrative and not in a limiting sense.

What is claimed is:

1. In combination with well bore apparatus adapted for insertion into awell bore containing a column of fluid, said apparatus having anelectrical circuit to be selectively controlled, a housing including atleast two chambers, one of said chambers being subject to well fluidpressure and the other chamber being pressure sealed; electrical controlmeans in said other chamber for controlling said electrical circuit;means normally spaced from said electrical control means and movableresponsive to pressure differentials between said chambers lforactuating said electrical control means; biasing means resistingmovement of said actuating means; and means for selectively setting thespacing between said actuating means and said electrical control meanswhereby the pressure differential required for actuation of theelectrical control means can be preselected.

2. In combination with well bore apparatus adapted for insertion into awell bore containing a column of fluid, said apparatus having anelectrical circuit to be selectively controlled, a housing including atleast two' chambers, one of said chambers being subject to well fluidpressure and the other chamber being pressure sealed; electrical controlmeans in said other chamber for controlling said electrical circuit;means normally spaced from said electrical control means and movableresponsive to pressure differentials between said chambers for actuatingsaid electrical control means; biasing means resisting movement of saidactuating means; and support means in said other chamber operativelyassociated with said electrical control means whereby said electricalcontrol means can be selectively positioned a predetermined distanceaway from said actuating means, said distance being proportionatelyrelated to the pressure differential acting to move said actuatingmeans.

3. In combination with well bore apparatus adapted for insertion into aWell bore containing a column of uid, said apparatus having anelectrical circuit to be selectively controlled, a housing including atleast two chambers, one of said chambers being subject to well fluidpressure and the other chamber being pressure sealed; electrical controlmeans in said other chamber for controlling said electrical circuit;means normally spaced from said electrical control means and movableresponsive to pressure ditferentials between said chambers for actuatingsaid electrical control means; biasing means resisting movement for saidactuating means; and means for supporting said electrical control meansyand for selectively positioning said electrical control means apredetermined distance away from said actuating means, said supportingand selectively positionable means being component parts of saidelectrical circuit, said distance being proportionately related to thepressure differential acting to move said actuating means.

4. In combination with well bore apparatus adapted for insertion in awell bore containing a column of fluid, said apparatus having anelectrical circuit to be selectively opened or closed, a housingincluding at least two chambers, one of said chambers being subject tohydrostatic well lluid pressure and the other chamber being normallysealed from hydrostatic well fluid pressure; seal means between saidchamber; a piston passing through said seal means and extending intoe-ach of said chambers, said piston being movable responsive to pressuredifferentials between said chambers; biasing means resisting movement ofsaid piston; switch means in said other chamber for opening or closingsaid circuit; means on said piston for actuating said switch means uponpredetermined travel of said piston; and means for selectively spacingsaid switch means from sai-d piston means a distance proportionatelyrelated to preselected pressure differentials to be developed for actionon said piston.

5. In combination with well bore apparatus adapted for insertion in awell bore containing a column of fluid, said apparatus having anelectrical circuit to be selectively opened or closed, a housingincluding at least two chambers, one of said chambers being subject tohydrostatic well uid pressure and the other chamber being normallysealed from hydrostatic well fluid pressure; seal means between saidchambers; a piston passing through said seal means and extending intoeach of said chambers, said piston being movable responsive to pressuredifferentials between said chambers; biasing means resisting movement ofsaid piston; switch means in said other chamber for opening or closingsaid circuit; means on said piston for actu-ating said switch means uponpredetermined travel of said piston; and means for supporting saidswitch means and for selectively positioning sai-d switch means apredetermined distance away from said actuating means, said supportingand selectively positionable means being component parts of saidelectrical circuit, said distance being proportionately related topressure differentials acting to move said piston.

6. In com-bination with well bore apparatus `adapted for insertion intoa well bore containing a column of fluid, said apparatus having aplurality of electrical circuits to be sequentially operated, a -housinghaving at least two chambers, one of said chambers being subject to welllluid pressures and another of said chambers being pressu-re sealed;electrical control means, including a selectively positionable switch insaid other chamber, for controlling said plurality of electricalcircuits; and means normally space-d from said selectively positionableswitch and movable -responsive to pressure differentials between saidchambers for actuating said switch, said actuating means being biasedagainst movement responsive to pressure differentials between saidchambers.

7. Apparatus as set forth in claim 6 and wherein the electrical controlmeans further includes a stepping switch operable in response torepetitive actuation of the selectively positionable switch forsequentially operating said plurality of electric-al circuits.

`8. Apparatus as set forth in claim 7 and wherein the electrical controlmeans further includes a delay means requiring a constant input signalfor a predetermined duration of time before an output signal isgenerated for actuating said stepping switch.

References Cited UNITED STATES PATENTS 2,543,823 3/1951 Barry 200-82 X3,029,872 4/1962 Hanes 166--63 3,105,550 lil/1963 Ehlert 166-653,223,184 12/1965 Jones et al 20G-82 X 3,246,707 4/1966 Bell 175-454CHARLES F. OCONNELL, Primary Examiner.

DAVID H. BROWN, Examiner.

